The main structure of prior art playpens includes four top rails contiguously linked by four top corner brackets, four bottom rails contiguously linked by four bottom brackets, four columns respectively extending between paired top and bottom corner brackets, a base extending between the bottom side rails and a mesh wall extending around the four columns. The top side rails and bottom side rails may be articulated at midpoints thereof to facilitate easy and compact storage of the playpen when not in use. However, the bottom corner brackets of prior art playpens also function as simple feet which, although providing stability do not allow the playpen to be rocked when a baby or infant therein is tired and should sleep.
In order to coax an infant into sleeping, the parents usually cradle the infant in their arms. However, the parents' arms ache after five or ten minutes of this action. When the parent places the infant on the floor of conventional playpen, the infant usually wakes up and cries which is inconvenient and distressing. The present application provides a creative and novel means for solving the problems mentioned above.